Soiith American Rotifer a. By J. Murray. 451 



Brazilian and Australian examples differ from Luck's figure, it 

 that be correct, in several characters. They are more elongate and 

 narrow ; posterior truncation is much smaller ; the ventral open- 

 ing is narrower and much longer. It is a very pretty graceful 

 animal. 



The ridges, except the middle one, do not run all the length of 

 the lorica. 



Brachionus mollis Hempel {60). 



The head is protected by a series of flexible hyaline plates, very 

 similar to those figured in Cathypna leontina (fig. 21&, in plate of 

 the Cathypnidae in this Journal). 



A variety (not figured) occurred in Eio, with two large mem- 

 branous projections from the sides of the foot-opening. 



Brachionus mulleri Ehr. Plate XVIII, figs. 47<x-47c. 



The species is usually characteristic of brackish water. In 

 the ponds of Eio several forms occurred. There was no form at 

 all like the type, as I have found it, for instance, in the Scilly 

 Isles. 



Variety (fig. 47a). — Large ; dorsal anterior spines completely 

 obsolete ; ventral margin 4-scalloped as usual. 



Variety (fig. 47&). — Of moderate size ; teeth equidistant, not 

 like saw-teeth ; ventral margin 4-scalloped. 



In the salt lagoon, Eio. 



Variety (fig. 47c). — Very small, teeth saw-like, reticulate or 

 spongy -looking ; ventral margin scalloped. 



In the salt lagoon, Eio. 



I do not profess to be able to pronounce upon the values of 

 these forms, but figure them for the benefit of the first monographist 

 who comes along. The smaller form appears to be constant and 

 sufficiently far from the type. 



Brachionus trahea sp. n. (Plate XVIII, figs. 48a, 48&). 



Specific Characters. — Large, elongate. Anterior dorsal margin 

 with six spines, the outer pair much the longest, the median pair 

 next, and the intermediate pair mere spicules or papillae ; posterior 

 processes very long, stout and recurved. 



Description. — Length about 360 yLt, greatest width 110 /i, outside 

 anterior spines 50-60 //,, median spines 30-40 /x, posterior pro- 

 cesses 160 /a. The body is highest behind, a little behind the 

 widest part, the thickness there (dorso-ventrally) being about 



2 H 2 



